A typical example of the key forming part of the keyboard of the electronic keyboard instrument is illustrated in FIG. 1. The key 1 is provided on a framework 2 of a metal in such a manner as to be rockable with respect to the framework 2. In detail, the framework 2 comprises a flat portion 3 formed with an opening 4, a front guide portion 5 formed with a vertical slit 6 and a rear vertical portion 7 providing a fulcrum for the key 1. The flat portion 3 supports a print-circuit board 8 with connecting rods 9 and 10, and an electrical switch 11 is provided on the printcircuit board 8 in such a manner as to be located beneath the opening 4. The electrical switch 11 has a pair of contacts of a conductive rubber electrically isolated from each other by a non-conductive rubber, so that the contacts are brought into contact with each other when a compressive force is exerted thereon.
The key 1 comprises a flat upper plate 12 where the player touches, a rear notch portion 13 merged with the flat upper plate 12, and a front guide plate 14 downwardly projecting from the lower surface of the flat upper plate 12 and loosely inserted in the vertical slit 6. A compression spring 15 is provided between the notch portion 13 and the flat portion 3, so that the rear notch portion 13 is urged to be pivotally connected to the rear vertical portion 7. However, when the flat upper plate 12 is pressed by the player, the key 1 is rockably moved toward the framework 2 against the compression spring 15 with a guidance of the front guide portion 5. The key 1 further comprises a pusher 16 downwardly projecting from the lower surface of the flat upper plate 12, and the leading end of the pusher 16 is located above the electrical switch 11. Then, when the key 1 is pressed, the pusher 16 is brought into contact with the electrical switch 11 and, then, a conduction path is established therebetween. The flat upper plate 12, the rear notch portion 13, the front guide plate 14 and the pusher as a whole is molded from a synthetic resin to form the key 1, however the key 1 is physically separated from the framework 2. Then, the individual keys should be assembled to the framework 2 while inserting the compression springs between the keys and the framework 2 for completing the keyboard.
A problem is encountered in the prior-art keyboard in complexity in construction due to a large number of parts and, accordingly, in time-consuming and elaborate labor for assemblage.